The overall objective will be to investigate hepatic zinc metabolism using isolated liver parenchymal cells in primary culture. The cells will be isolated by the collagenase perfusion technique from livers of rats of varying dietary zinc status. The kinetics of zinc uptake by efflux from hepatocytes will be measured. The role played by specific serum constituents that are potential donors and acceptors of zinc, e.g., albumin, transferrin and gamma-2-macroglobulin which may be components of the uptake and efflux mechanism, will be examined as will the influence of specific hormones and mediators e.g. hydrocortisone, cAMP and leukocytic endogenous mediator on these processes. The subcellular sites of zinc deposition will be investigated as a function of external zinc-metallothionein, a low molecular weight hepatic zinc-binding protein, to zinc uptake and retention will be investigated via incorporation of 65Zn as well as 35S and 14C-amino acids into this protein and the influence of actinomycin D, cordycepin and cycloheximide, thereon. These parameters will be examined in cells from animals fed various levels of zinc and will be compared to responses observed in animals in vivo during a variety of nutritional and disease states.